Question

Medical researchers are studying a certain genetic trait found in two populations of people, W and X. From an independent random sample of people taken from each population, the difference between the sample proportions of people who carried the trait (W minus X) was 0.22. Under the assumption that all conditions for inference were met, a hypothesis test was conducted using the following hypotheses.

H0 : pW=pXHa : pW > p XHo : pW= pX Ha: pW >pX

The p-value of the test was 0.03. Which of the following is the correct interpretation of the p-value?
a. The probability of selecting a person from population W who carries the trait is 0.22, and the probability of selecting a person from population X who carries the trait is 0.03.
b. If the proportions of all people who carry the trait are the same for both populations, the probability of observing a sample difference of at least 0.22 is 0.03.
c. If the proportions of all people who carry the trait are the same for both populations, the probability of observing a sample difference of 0.22 is 0.03.
d. If the difference in proportions of people who carry the trait between the two populations is actually 0.22, the probability of observing that difference is 0.03.
e. If the difference in proportions of people who carry the trait between the two populations is actually 0.03, the probability of observing that difference is 0.22.

Answer 1

If the proportions of all people who carry the trait are the same for both populations, the probability of observing a sample difference of at least 0.22 is 0.03

Explanation:

Given the hypothesis :

H0 : pW = pX

Ha : pW > pX

W - X = 0.22

Pvalue = 0.03

Since the Pvalue gives the probability of obtaining a value or result figure which is atleast as extreme as the observed value. The observed value here is 0.22 resulting from the difference in W and X (W - X).

This can thus be interpreted to mean ; going by the Null (difference between W and X) ; the probability of obtaining a value of atleast 0.22 as difference is 0.03